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Location Tanzania, Arusha
Central coordinates 36o 0.00' East  2o 25.00' South
IBA criteria A1, A3, A4i, A4iii
Area 154,000 ha
Altitude 610 m
Year of IBA assessment 2001





Site description Lake Natron is a shallow soda-lake in a closed basin on the floor of the Eastern Rift Valley. It extends 58 km south from the Kenyan border with a mean width of 15 km. Although its surface area can reach 850 km², the maximum depth is only 50 cm. There are considerable seasonal fluctuations in surface area between the middle of the dry season (November–December) and the end of the rains (April–May). The water is highly saline with chloride concentrations reaching 65,000 mg/litre and is unsuitable for direct human and livestock use. The lake’s principal inflow is the perennial Ewaso Ngiro river which rises on the Mau Escarpment in Kenya and flows southwards along the eastern edge of the Nguruman Hills. Seasonal drainage from within Tanzania includes major rivers from the Loita Hills (rising in Kenya) and Longido mountains in the north-west, the Gol mountains in the west, the Ngorongoro Highlands to the south and minor streams from Mount Gelai in the south-east.The surrounding land is dry bush dominated by Acacia thorn-trees, inhabited by pastoralist Masai. There is some seasonal cultivation along the riverbanks and a small settlement in the south associated with a minor soda-extraction plant and a few small tourist camps. Otherwise the general area is sparsely populated, the lack of fresh water in the dry season controlling the populations of both man and livestock. Engaruka is a shallow depression in the Rift Valley 50 km north-north-east of Lake Manyara and 58 km south south-east of Lake Natron. The centre of the depression is a semi-permanent lake covering in excess of 400 ha. Surrounding this lake is a swamp that can extend for up to 3 km, especially to the north and south-east. Beyond this lies a shallow plain which is occasionally inundated over a further 4,000 ha. During dry years the area is a rather featureless plain fringed with low acacia scrub and heavily grazed by herds of Masai cattle and goats.

Populations of IBA trigger species

Species Season Period Population estimate Quality of estimate IBA Criteria IUCN Category
Trachyphonus darnaudii resident  2000  present  A3  Not Recognised 
Black-throated Barbet Tricholaema melanocephala resident  2000  present  A3  Least Concern 
Red-and-yellow Barbet Trachyphonus erythrocephalus resident  2000  present  A3  Least Concern 
Yellow-necked Francolin Pternistis leucoscepus resident  2000  present  A3  Least Concern 
Lesser Flamingo Phoeniconaias minor breeding  1994  500,000 breeding pairs  A1, A4i  Near Threatened 
Eastern Chanting-goshawk Melierax poliopterus resident  2000  present  A3  Least Concern 
Buff-crested Bustard Lophotis gindiana resident  2000  present  A3  Least Concern 
Black-faced Sandgrouse Pterocles decoratus resident  2000  present  A3  Least Concern 
Fischer's Lovebird Agapornis fischeri resident  2000  unknown  A3  Near Threatened 
White-bellied Go-away-bird Criniferoides leucogaster resident  2000  present  A3  Least Concern 
Sombre Nightjar Caprimulgus fraenatus resident  2000  present  A3  Least Concern 
Donaldson-Smith's Nightjar Caprimulgus donaldsoni resident  2000  present  A3  Least Concern 
Abyssinian Scimitarbill Rhinopomastus minor resident  2000  present  A3  Least Concern 
Von der Decken's Hornbill Tockus deckeni resident  2000  present  A3  Least Concern 
Rosy-patched Bush-shrike Rhodophoneus cruentus resident  2000  present  A3  Least Concern 
Long-tailed Fiscal Lanius cabanisi resident  2000  present  A3  Least Concern 
Taita Fiscal Lanius dorsalis resident  2000  present  A3  Least Concern 
Red-throated Tit Parus fringillinus resident  2000  present  A3  Least Concern 
Ashy Cisticola Cisticola cinereolus resident  2000  present  A3  Least Concern 
Grey Wren-warbler Camaroptera simplex resident  2000  present  A3  Least Concern 
Banded Warbler Sylvia boehmi resident  2000  present  A3  Least Concern 
Scaly Chatterer Turdoides aylmeri resident  2000  present  A3  Least Concern 
Rufous Chatterer Turdoides rubiginosa resident  2000  present  A3  Least Concern 
Northern Pied-babbler Turdoides hypoleuca resident  2000  unknown  A3  Least Concern 
White-breasted White-eye Zosterops abyssinicus resident  2000  present  A3  Least Concern 
Hildebrandt's Starling Lamprotornis hildebrandti resident  2000  present  A3  Least Concern 
African Grey Flycatcher Bradornis microrhynchus resident  2000  present  A3  Least Concern 
Kenya Violet-backed Sunbird Anthreptes orientalis resident  2000  present  A3  Least Concern 
Swahili Sparrow Passer suahelicus resident  2000  present  A3  Least Concern 
Blue-capped Cordonbleu Uraeginthus cyanocephalus resident  2000  present  A3  Least Concern 
Purple Grenadier Uraeginthus ianthinogaster resident  2000  present  A3  Least Concern 
Red-rumped Waxbill Estrilda charmosyna resident  2000  present  A3  Least Concern 
Steel-blue Whydah Vidua hypocherina resident  2000  present  A3  Least Concern 
Straw-tailed Whydah Vidua fischeri resident  2000  present  A3  Least Concern 
Pangani Longclaw Macronyx aurantiigula resident  2000  present  A3  Least Concern 
White-bellied Canary Serinus dorsostriatus resident  2000  present  A3  Least Concern 
A4iii Species group - waterbirds breeding  1994  1,000,000-2,499,999 individuals  unknown  A4iii   

Protected areas

Protected area Designation Area (ha) Relationship with IBA Overlap with IBA (ha)  
Lake Natron Basin Wetlands of International Importance (Ramsar) 22,478,100 protected area contains site 154,000  

Local conservation groups The local conservation group below is working to support conservation at this IBA.

Name Year formed
ILKISONGO PASTORAL INITIATIVES (IPI) 1999

Habitats

IUCN habitat Habitat detail Extent (% of site)
Artificial - terrestrial   4%
Wetlands (inland)   39%
Grassland   56%

Land use

Land-use Extent (% of site)
agriculture -
tourism/recreation -
other -
Notes: Small-scale soda extraction.

Other biodiversity There are considerable numbers of ungulates in the ecosystem, including Oryx gazella, while Lake Natron is the northern limit for wildebeest Connochaetes migrating north from Tarangire National Park.

Related state of the world's birds case studies

References Baker (1997), Bartholomew and Pennycuick (1973), Brown (1955), Grzimek and Grzimek (1960), Guest and Stevens (1951), Kahl (1975), Rose and Scott (1997), Woodworth (1995).

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Recommended citation  BirdLife International (2014) Important Bird Areas factsheet: Lake Natron and Engaruka basin. Downloaded from http://www.birdlife.org on 31/08/2014

To provide new information to update this factsheet or to correct any errors, please email BirdLife